/*
 * jccolext.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * libjpeg-turbo Modifications:
 * Copyright (C) 2009-2012, D. R. Commander.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains input colorspace conversion routines.
 */


/* This file is included by jccolor.c */

/*
 * Convert some rows of samples to the JPEG colorspace.
 *
 * Note that we change from the application's interleaved-pixel format
 * to our internal noninterleaved, one-plane-per-component format.
 * The input buffer is therefore three times as wide as the output buffer.
 *
 * A starting row offset is provided only for the output buffer.  The caller
 * can easily adjust the passed input_buf value to accommodate any row
 * offset required on that side.
 */

INLINE LOCAL(void) rgb_ycc_convert_internal(j_compress_ptr cinfo,
   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
   JDIMENSION output_row, int num_rows)
{
   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
   register int r, g, b;
   register INT32 * ctab = cconvert->rgb_ycc_tab;
   register JSAMPROW inptr;
   register JSAMPROW outptr0, outptr1, outptr2;
   register JDIMENSION col;
   JDIMENSION num_cols = cinfo->image_width;

   while (--num_rows >= 0)
   {
      inptr = *input_buf++;
      outptr0 = output_buf[0][output_row];
      outptr1 = output_buf[1][output_row];
      outptr2 = output_buf[2][output_row];
      output_row++;
      for (col = 0; col < num_cols; col++)
      {
         r = GETJSAMPLE(inptr[RGB_RED]);
         g = GETJSAMPLE(inptr[RGB_GREEN]);
         b = GETJSAMPLE(inptr[RGB_BLUE]);
         inptr += RGB_PIXELSIZE;
         /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
          * must be too; we do not need an explicit range-limiting operation.
          * Hence the value being shifted is never negative, and we don't
          * need the general RIGHT_SHIFT macro.
          */
         /* Y */
         outptr0[col] = (JSAMPLE)
            ((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] + ctab[b + B_Y_OFF])
            >> SCALEBITS);
         /* Cb */
         outptr1[col] = (JSAMPLE)
            ((ctab[r + R_CB_OFF] + ctab[g + G_CB_OFF] + ctab[b + B_CB_OFF])
            >> SCALEBITS);
         /* Cr */
         outptr2[col] = (JSAMPLE)
            ((ctab[r + R_CR_OFF] + ctab[g + G_CR_OFF] + ctab[b + B_CR_OFF])
            >> SCALEBITS);
      }
   }
}


/**************** Cases other than RGB -> YCbCr **************/

/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles RGB->grayscale conversion, which is the same
 * as the RGB->Y portion of RGB->YCbCr.
 * We assume rgb_ycc_start has been called (we only use the Y tables).
 */

INLINE
LOCAL(void)
rgb_gray_convert_internal(j_compress_ptr cinfo,
   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
   JDIMENSION output_row, int num_rows)
{
   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
   register int r, g, b;
   register INT32 * ctab = cconvert->rgb_ycc_tab;
   register JSAMPROW inptr;
   register JSAMPROW outptr;
   register JDIMENSION col;
   JDIMENSION num_cols = cinfo->image_width;

   while (--num_rows >= 0)
   {
      inptr = *input_buf++;
      outptr = output_buf[0][output_row];
      output_row++;
      for (col = 0; col < num_cols; col++)
      {
         r = GETJSAMPLE(inptr[RGB_RED]);
         g = GETJSAMPLE(inptr[RGB_GREEN]);
         b = GETJSAMPLE(inptr[RGB_BLUE]);
         inptr += RGB_PIXELSIZE;
         /* Y */
         outptr[col] = (JSAMPLE)
            ((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] + ctab[b + B_Y_OFF])
            >> SCALEBITS);
      }
   }
}

/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles extended RGB->plain RGB conversion
 */

INLINE
LOCAL(void)
rgb_rgb_convert_internal(j_compress_ptr cinfo,
   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
   JDIMENSION output_row, int num_rows)
{
   register JSAMPROW inptr;
   register JSAMPROW outptr0, outptr1, outptr2;
   register JDIMENSION col;
   JDIMENSION num_cols = cinfo->image_width;

   while (--num_rows >= 0)
   {
      inptr = *input_buf++;
      outptr0 = output_buf[0][output_row];
      outptr1 = output_buf[1][output_row];
      outptr2 = output_buf[2][output_row];
      output_row++;
      for (col = 0; col < num_cols; col++)
      {
         outptr0[col] = GETJSAMPLE(inptr[RGB_RED]);
         outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]);
         outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]);
         inptr += RGB_PIXELSIZE;
      }
   }
}
